Thermostatic control for electric heaters



Sept. 17, 1929. KUHN 1,728,291

THERMOSTATIC CONTROL FOR ELECTRIC HEATERS Filed Oct. 5, 1927 i l'llll 4 2g l/X /7 4 "223 lit LA 25' f H 2 6 /7 X5 V awuawlfo Patented Sept. 17, 1929.

UNITED STATES PATENT OFFICE FRANK KU HN, OF DETROIT, MICHIGAN, ASSIGNOR TO AMERICAN ELECTRICAL HEATER COMPANY, OF DETROIT, MICHIGAN, .A CORPORATION OF MICHIGAN THERMOS TATIC CONTROL FOR ELECTRIC HEATERS Application filed October 5, 1927. Serial No. 224,223.

This invention relates generally to thermostatic controls for electric heaters such as electrically heated laundry irons, and consists of certain novel features of construction, combinations and arrangements of parts as will be hereinafter more fully described and particularly pointed out in the appending claims.

In the accompanying drawing Figure 1 is a fragmentary side elevation of an iron embodying my invention, with parts broken away and showing the thermostatically operated switch.

Figure 2 is a perspective view of a portion of the iron with the hood removed.

Figure 3 is a section on the line 3-3 of Figure 4. I

Figure 4 is a section on the line 4-4 of Figure 1.

Figure 5 is a detailed perspective view of the bracket assembly.

Referring now to the drawing, T have illustrated an electrically heated laundry iron in which 1 is the heat distributing 2 base, 2 is the electrical heating unit above the base, 3 is the pressure plate for clamping the unit to the base, 4 is the hood provided with the usual ,handle 5, and 6 is a stud rising from the base and having so threaded portions? and 8 that are engaged by suitable nuts 9 and 10 respectively for clamping the plate 3 and hood 4 in proper assembled position.

In the present instance the usual terminal contacts or pins 11 and 12, a thermostat 13 and suitable electrical conductor bars 14, 15 and 16 respectively, are all mounted upon a single plate or bracket 17 which in turn is held upon the pressure plate 3 by means of the nut 9. As shown, this bracket 17 serves only as a mechanical support for the parts just mentioned, and has a substantially flat base 18 and two laterally spaced upwardly and forwardly extending arms 19 and 19.

With this construction the terminal contacts 11 and 12project through an insulator block 20 carried by the arms 19 and 19, and are electrically connected at their inner ends onto the conductor bars 14 and-15 which are also embedded in the block 20 and project laterally therefrom. The other conductor bar 16 is held by a suitable screw 21 upon the base 18 of the bracket 17, and is insulatcd by suitable means such as mica from both the screw 21 and base 18. The thermostat 13 is preferably in theform of a short, narrow arm and is secured at one end upon but insulated from the conductor bar 16. Preferably the screw 21, used to secure the bar 16 in place, is also used as the attaching means for the thermostat. The free end of the thermostat is electrically connected to the conductor bar 15 by means of a light, substantially U-shaped spring 22, that in turn is terminally connected to said parts 15 and 13. Contact buttons 23 and 24 are carried by the thermostat 13 and conductor bar 16 respectively, and are normally held together by the thermostat 13 so as to electrically connect the U-shapecl spring 22 to the bar 15.

' The heating unit 2 is of the armored type and has the two resistor wires 25 and 26 extending upwardly therefrom at the rear end thereof and connected respectively to the conductor plates 14- and 15. Thus normally the current passes through the resistor of the heating unit 2 and the thermostat 13, but when the temperature of the base exceeds a pre-determined degree, the thermostat 13 will warp and cause the contact buttons 23 and 24 to be separated, thereby breaking the electric circuit and preventing further heat generation.

From the foregoing description it will be apparent that I have provided a compact and durable bracket assembly which is simple in construction, can be manufactured at a comparatively low cost and which as a unit may be easily and quickly attached to the pressure plate by the usual stud 6 and nut 9. Repairs or replacements of parts or of the entire bracket assembly may be easily made. Moreover, the construction and arrangement of the thermostat is such that there is a quick response to variations in heat.

While it is believed that from the foregoing description, the nature and advantage of my invention will be readily apparent, I desire to have it understood that I do not limit myself to what is herein shown and described and that such changes may be resorted to when desired as fall within the scope of what is claimed.

What I claim as my invention is:

1. A sub-assembly for electrical heaters including a bracket having a substantially flat base and a pair of upstanding arms, an insulator block carried by said arms, terminal contacts carried by said insulator block, and a thermostatic switch carried by said base and electrically connected to one of said contacts.

2. A sub-assembly for electrical heaters comprising a bracket having a base portion and a pair of upstanding arms, an insulator block carried by said arms, electrical conductor bars carried by said block and insulated from each other, terminal contacts electrically connected respectively to said bars, and a thermostatic switch carried by said base and electrically connected to one of the bars aforesaid.

3. A sub-assembly for electrical heaters comprising a bracket having a substantially fiat base, and an electrical conductor bar located above but insulated from said base, a thermostatic member located above but insulated from said conductor bar, contact buttons carried by said bar and thermostatic member respectively and normally incontact with each other, and 'a common securing means for said thermostatic member and bar carried by the base aforesaid of said bracket.

a. A. sub-assembly for electrical heaters comprising a bracket having a base and a pair of upstanding arms, an electrical conductor bar upon but insulated from said base, a thermostat upon but insulated from the said bar, contact buttons secured to said bar and-thermostat respectively and normally in contact with each other, an insulated block carried by said arms, electrical conductor bars carried by said block and insulated from each other, and an electrical connection between 7 one of said contact buttons aforesaid and -one of said last mentioned conductor bars, 

